PMC

ND4, ND7, ND10, ND12: specimen from non-diabetic subjects. D4, D8-D10: specimens from subjects with T2D. All listed by the ascending order of age in each group.

A: Pancreatic sections immunostained for insulin (green), glucagon (red), somatostatin (white) and nuclei (blue) of relatively young and healthy subjects. ND1: 15-yr, ND3: 24-yr, and ND4: 41-yr. B: Non-diabetic and aged subjects. ND11: 63-yr, ND13: 73-yr, and ND15: 81-yr. C: Subjects with T2D. D2: 42-yr, D9: 72-yr, and D11: 75-yr.

A: Mean relative frequencies of islet sizes and cellular compositions (B: alpha-cell fraction, C: beta-cell fraction, and D: delta-cell fraction) depending on islet size in non-diabetic (gray; 8903 islets with n = 14) and T2D (color; 7929 islets with n = 12) subjects (mean ± SEM). The numbers in parentheses represent effective islet diameters (µm) corresponding to the given logarithmic dimensionless islet areas. Student's t-test compared the results between non-diabetic and T2D subjects at each size bin with *P<0.05, **P<0.001, and ***P<0.0001.

A: Probabilities of delta-delta, delta-beta, and delta-alpha cell contacts in non-diabetic subjects (blue; 6886 islets with n = 14). Those were compared with the theoretical estimation for random mixtures of cells (gray) where cellular compositions were the same with the individual islets in non-diabetic subjects (mean ± SEM). B: Comparison between non-diabetic (blue) and T2D (red; 5359 islets with n = 12) subjects. Note that scattered single endocrine cells are excluded in the calculation because contacting cells does not exist for them. The numbers in parentheses represent effective islet diameters (µm) corresponding to the given logarithmic dimensionless islet areas. Student's t-test compared the results between non-diabetic and T2D subjects at each size bin with *P<0.05, **P<0.001, and ***P<0.0001.

A: In non-diabetic subjects (ND1–ND14), relative frequency of islet size (gray bar) and ratios of alpha (red), beta (green), and delta (blue) cells within islets were plotted against islet size; means ± SEM. B: Results in T2D patients (D1–D12). Note that islet size is presented as a logarithmic scale considering the high number of small islets and the low number of large islets. In addition, we divided islet areas by the single-cell area, 170 µm² , to make them as dimensionless values representing the number of cells in a given islet area. The conversion between logarithmic islet area (logarithmic) and effective diameter (µm) is shown.

A: Inter-subject comparison. Total islet cell composition (beta-cells in green, alpha-cells in red, and delta-cells in blue) in individual non-diabetic subjects (a) and T2D patients (b). B: Morphological changes observed in large islets. Representative islets are pseudo-colored models of actual islets based on immunohistochemical images composed of beta-cells (green), alpha-cells (red), and delta-cells (white). From left to right: compacted endocrine cell arrangement, relatively sparse architecture, the presence of a population of cells lacking cytosolic hormones (blue), and cyst formation containing necrotic materials (purple). Corresponding small islets from the same sections in a to d are shown in e to h.

A: Virtual slice view of a human pancreatic section (ND11) immunostained for insulin (green), glucagon (red), somatostatin (white) and nuclei (blue). A series of contiguous images of a specimen is collected (illustrated as boxed panels) and merged into a single image montage (i.e. virtual slice; arrowed). A composite is made by merging four overlapping virtual slice images. B: Views of each channel showing cellular composition. a. beta-cells, b. alpha-cells, c. delta-cells, and d. composite of all three endocrine cells. Note that there is no overlap among the endocrine cell fractions. Corresponding converted 8-bit masks after automatic thresholidng are shown in e. A contour shown in e (a red line) is used to measure islet area, which includes non-labeled area (e.g. capillaries). Based on the captured center coordinates of each cell type within the given islet, its architecture is reconstructed in f.

A: A simple example to calculate cellular compositions and probabilities of contact between cell types in an islet consisting of 3 alpha- (red) and 4 beta- (green) cells. Lines represent contacts between neighboring cells. B: two examples of distinctive architectures: random mixture of cells (left) and a regular structure (right) where cellular composition is the same (alpha:beta = 3∶7). The numbers in parentheses are the probabilities of contact between cell types in the random cell mixture, which are theoretically estimated as (Pαα  = Pα ×Pα, Pββ  = Pβ ×Pβ, Pαβ  = Pα ×Pβ +Pβ ×Pα). C: Probabilities of alpha-alpha, beta-beta, and alpha-beta cell contacts in non-diabetic subjects (blue; 6886 islets with n = 14). Those were compared with the theoretical estimation for random mixtures of cells (gray) where cellular compositions were the same with the individual islets in non-diabetic subjects (mean ± SEM). D: Comparison between non-diabetic (blue) and T2D (red; 5359 islets with n = 12) subjects. Note that scattered single endocrine cells are excluded in the calculation because contacting cells does not exist for them. The numbers in parentheses represent effective islet diameters (µm) corresponding to the given logarithmic dimensionless islet areas. Student's t-test compared the results between non-diabetic and T2D subjects at each size bin with *P<0.05, **P<0.001, and ***P<0.0001.